1. Field of the Invention
The present invention relates to an axial-gap type rotating electrical machine.
2. Background Technology
Conventionally, commercial market has required for a rotating electrical machine such as electric motor or electric generator to be thin and compact in size or structure, and particularly, in these days, as a countermeasure to global warming tendency, requirement for energy saving and high efficiency has been increased. Moreover, it has been further strongly required for the rotating electrical machine to have low vibration and low noise as well as cheap cost.
A conventional technology related to a general axial-gap type rotating electrical machine provides an effective structure for making flat and thin, and when a rotor is formed into disc shape, an inertia is made small, so that such rotating electrical machine is effective for a constant speed operation and variable speed operation, which has been therefore attractive to attention in these days. However, in comparison with a radial-gap type rotating electrical machine, it is difficult to make small the air-gap, which adversely affects on high torque requirement and high efficiency requirement.
On the other hand, the following patent document has been provided as a technology for achieving related high torque by increasing an opposing area.